DE102006059233A1 - Energy storing in and storing out method for use in e.g. sea, involves permitting lifting body to be raised to smaller liquid depth in reverse direction for storing out energy so that energy is converted into electrical energy by converter - Google Patents

Abstract

The method involves immersing an energy storage medium i.e. lifting body (6) in a liquid (1), where the body has a specific weight that is smaller than that of the liquid. The body is moved from a low energy potential to higher energy potential and is lowered into a large liquid depth for obtaining a high energy potential, for directly storing in energy. The body is permitted to be raised to a smaller liquid depth in a reverse direction, for storing out energy, so that energy is converted into electrical energy using a converter (5) i.e. generator. An independent claim is also included for a storage device for alternatively storing in and storing out of energy for temporary generation of electrical energy.

Description

The The invention relates to a method for the alternate injection and withdrawal of energy in order to temporary Generation of electrical energy, in which an energy storage medium for storage by means of a drive of a low energy potential by overcoming a height difference is transported to a high energy potential and there on call can be held and in which the energy storage medium moved to the withdrawal in the opposite direction and the case energy released over a converter is converted into electrical energy. The invention further relates to a memory device for performing this Process.

For a safe Supply of the electricity network with electricity it is necessary to increase the amount of electricity the above to adjust the day to fluctuating demand. To a desired adaptability to insure in addition to the base load power plants medium power and peak power plants, for example Gas turbine and internal combustion engine power plants, the day if necessary can be approached and departed several times and by short journey times and high power change speeds distinguished.

the same purpose serve storage facilities, where energy in one Energy storage medium stored and quickly when needed again can be stored. The storage takes place in case of oversupply of electricity, because the electricity is then cheap, while the Withdrawal from a sub-bid to supply additional electrical energy takes place. This leads to greater network compatibility and adjusts the electricity from the base load power plants to the fluctuating one Demand. Through storage plants, electricity price changes can be economical be used by selling cheap electricity in case of oversupply, but is fed into the energy storage and later at Energy shortage at a higher price is fed into the power grid.

fluctuation problems But there is not only on the demand side, but also at the feeding of electricity into the electricity grid. These are caused by the increasing number of power plants using renewable or renewable energies are operated, the strong fluctuations subject. Which includes in particular wind and solar power plants. Their share in total electricity generation is now so big that it in case of lack of wind and / or too little sunlight too short-term voltage drops comes in the power grid, with 30% of the voltage drops less than a second to last; to endure, to continue.

When Storage facilities have long been known pumped storage plants, in which in periods from surplus electricity Water as an energy storage medium from a geographically low lying Water reservoir, such as a river or a lake, in one higher altitude Reservoir is pumped up and thereby the energy potential of the water according to the thereby overcome height difference elevated becomes. When electricity is needed, the dammed up water is pumped through large downpipes into water turbines fed at the level of the low water reservoir stand. Such pumped storage plants have a relatively long reaction time, and their further dissemination is contrary to the fact that it is in Germany no more suitable locations, an expansion of the capacities not possible anymore is. In addition, by evaporation of the usually very large water surface stand-by losses and by the water flow in the pipes friction losses occur, which increase the efficiency of the Impaired pumped storage plant.

Besides are more storage known. For compressed air storage units become energy from excess electricity Compressed air masses and stored for example in salt caverns. When power is needed, this air is taken and can help, a Power gas turbine. To increase efficiency is at adiabatem Save the heat generated during compaction also stored and supplied to the turbine as needed. A disadvantage of such compressed air storage units is their lower, between 42 and 55% efficiency. In addition, such storage only be provided where appropriate geological conditions (size underground caverns, salt domes etc.) allow the storage of compressed air.

Known are also flywheel storage, where a flywheel with excess energy set in rotation, the energy stored as rotational energy becomes. If necessary, the flywheel is braked and thereby the previously stored stored energy. Disadvantage of flywheel storage is the relatively low storable amount of energy and therefore the relatively low withdrawal times. In addition, caused by friction high stand-by losses of the order of magnitude between 3 to 20% per hour, allowing such energy storage for use over a longer period are not suitable.

A Storing excess electrical Energy can also be over Capacitors take place, which are discharged when power is needed. Of the The disadvantage of capacitors lies in the small amount of energy that can be stored. That is why the Duration of the withdrawal less than 1 second. There are also capacitors expensive.

A another possibility The storage consists in superconducting magnetic energy storage. In a coil can excess energy be stored in the form of a magnetic field, using superconductors used to minimize the losses in the current flow through the coil become. Such energy storage are still in the development stage. The necessary cooling the superconductor leads to a loss in the energy balance. In addition, the price is still very high and the potential energy storage only mediocre.

One Classic energy storage are batteries in which excess electricity can be stored in the form of electrochemical energy. A major disadvantage of batteries is their limitation on the number of charge cycles with the result that it still replaces a certain charge cycle number Need to become. Furthermore Batteries are an expensive energy storage medium.

Finally exists even the possibility of excess electricity by splitting water into hydrogen and oxygen by means of To store electrolysis, i. by storing the stream in the form chemical energy. about a fuel cell can recover electricity from hydrogen and oxygen become. The main disadvantage of this form of energy storage is in the relatively low overall efficiency on the order of only 25%. In addition, there is still no satisfactory solution for storage of hydrogen for extended periods of time it then comes to hydrogen losses, the total balance still continue to worsen.

Of the Invention is based on the object, a method for alternating Storage and withdrawal of energy for the purpose of temporary generation of electrical energy Energy can be designed so that large amounts of energy can be stored and accordingly great benefits are available, no standby losses occur, high efficiency is achieved, a high number of cycles is possible and the memory device for performing the method low specific price. Another task is to design a memory device with which the method is performed can.

to solution the first part of the task is based on a procedure in which - as in a pumped storage plant - a Energy storage medium for storage by means of a drive of a low energy potential by overcoming a height difference is transported to a high energy potential and there on call can be held and in which the energy storage medium moved to the withdrawal in the opposite direction and the case energy released over a converter is converted into electrical energy. In deviation to the pumped storage plant, where the energy storage medium water is, the method according to the present invention is characterized in that a buoyancy body immersed in a liquid is used as the energy storage medium whose specific gravity is lower than that of the liquid, and that the buoyancy body for storage in a large liquid depth is lowered in order to achieve a high energy potential and there is ready for take-off and that the buoyancy body for the withdrawal in Direction to the low fluid depth can be driven up while using the converter electrical Energy generated.

basic idea The invention is therefore to energy in a buoyant body Save that in a liquid is immersed. The shipment of the buoyant body to a predetermined depth happens by means of a drive of whatever kind. There can the buoyancy body be held ready for call. When there is a demand for electricity, the buoyant body will come up calmly. The buoyancy body is connected to the converter, for example a generator, in such a way that that the buoyancy movement of the buoyant body in the converter into electrical Energy is converted. This can then be e.g. fed into the electricity grid become.

The inventive method is characterized by a number of advantages. Apart from Pumped storage are opposite the other storage power plants store significantly larger amounts of energy. and available. The size of the storable Energy quantity can be determined by the size of the volume the buoyancy body and the height difference between the movement end points of the buoyant body in a wide range the respective needs be adjusted. The efficiency of storage is higher than with all other known energy stores, because the energy is direct is stored in mechanical energy and during the withdrawal only small losses caused by the flow resistance of the drive body. On top of that, in the provision of the stored energy no standby losses occur. The storage can be besides - apart on the life of the mechanical parts involved in the system - arbitrary to repeat. An apparatus for performing the method records by a low in terms of storable energy specific price.

In addition, the process can be used very flexibly. Although the prerequisite for its implementation is the presence of a liquid reservoir with a depth sufficient for the respective storage requirements. For small requirements, this can already be a well dimensioned. Particularly suitable However, the process for use in artificial lakes, such as reservoirs, natural lakes or in the sea, with corresponding water depths in moving liquid reservoirs such as rivers. With the method according to the invention can be Aussticherungszeiten of minutes to a few hours and thereby achieve outputs of several 100 MW.

One Another advantage of the method according to the invention is that the buoyancy body and thus the energy storage medium is located below the liquid surface and therefore invisible with the consequence that through it no optical impairment is caused.

It It is understood that not only a single buoyancy body, but several buoyancy bodies available could be, used in the process simultaneously or alternately come. Likewise several drives for the storage of energy and also several converters for generation be provided of electrical energy. The used so far Einzahl is therefore not to be understood that only a single buoyancy body, drive or converters are present.

According to the main purpose the method according to the invention is provided that the electrical generated by the converter Energy in an electricity grid - there it can also be a local island grid - fed is, and preferably only when power is needed and voltage dips avoided should be. For the Storage of energy by means of the buoyant body should an electric drive can be used. This opens the Possibility, the electrical energy for the drive from the electricity grid to win, and preferably when there is an excess of electricity exists and therefore electricity can be purchased relatively inexpensively. In both cases occurs a current smoothing one, the electricity lines better utilization and keeps the mains voltage and frequency stable.

The inventive method is particularly suitable in conjunction with power plants, in which electricity produced from renewable energy sources that fluctuate. Such power plants are in particular wind and photovoltaic solar power plants whose electricity generation in case of too little wind or too little light can. It can also be power plants that use the energy of ocean currents. In all cases can with the inventive method temporarily electrical Electricity fed into the electricity grid and thus the generation of power by the power plant will be replaced. Is sufficient wind or light or sea current available, the through the power plant used to be used to power the drive supplied to become the buoyant body lower again.

Provided The power plant is designed as a wind power plant, comes next to the above-described electric drive also a mechanical drive in Question, with the help of the buoyancy body for the purpose of storage is lowered by energy. It forms by wind power in Rotation staggered rotor the mechanical drive. Both alternatives activities to lead to a smoothing electricity production at the place of production itself be better utilized.

To Another feature of the invention is that as an energy storage medium additionally a weight body - it can too several weight bodies be - used whose specific gravity is greater than that of the liquid, and that the weight body for storage by means of a drive - this can also drive for the Lowering the buoyancy body be - raised and is there on call durable and that the weight body to Allowing withdrawal is lowered, wherein the weight body with so a converter - here it may also be the transducer coupled to the buoyant body act - connected is that the lowering movement is converted into electrical energy becomes. The movement of the weight body can also be done above the liquid surface, especially there the flow resistance is comparatively low. For optical reasons, however, it may make sense be that the range of motion of the weight body as that of the buoyant body below the Liquid surface is, the weight body so moved between a small and a large liquid depth back and forth becomes. The weight body supports the storage effect of the buoyant body.

With regard to the second part of the object relating to the storage device, the invention consists in that the energy storage medium is designed as a buoyant body immersed in a liquid whose specific gravity is lower than that of the liquid, and in that the buoyant body is between a large and a buoyant body a low fluid depth is movably guided and connected to the drive such that the buoyancy body is lowered by the drive from the low fluid depth into the large fluid depth, and that the buoyant body is connected to the converter such that its movement in the direction of the low Fluid depth is converted into electrical energy. The device according to the invention is distinguished by the advantages already mentioned in connection with the method. The memory can be be formed as a single storage plant, which is used in deep lakes or in the sea and is connected via cables to the electricity grid for the purpose of stabilizing the voltage and frequency. Depending on the available depth and thus to be realized height difference between low and large liquid depth and thus appropriate dimensioning of the device and the buoyant body can be achieved capacities of some 100 MWh and powers of some 100 MW.

Of the Drive for the lowering of the buoyant body can be out as an electric motor and the converter out as a generator be. If both are present, it lends itself to electric motor and Form generator as a unit, so that the same device in the Storage as electric motor and during the withdrawal as generator is working.

To Another feature of the invention is that the anterieb and / or the converter with a local electricity network supra-regional Dissemination is linked to that generated by the converter electric power can be fed into the electricity grid when needed. The Connection to the electricity grid allows it for the case that the drive for the lowering of the buoyant body is designed as an electric motor, the electrical energy for this from the Electricity network too win, and preferably when an excess of electricity exists and therefore electricity can be purchased relatively inexpensively.

The inventive device is particularly suitable for integration into a power plant, and indeed preferably such a power plant, the electric current fluctuating from generated renewable energy. Such power plants are especially wind power plants with a rotor and a generator and / or Solar power plants based on solar collectors and / or photovoltaic elements and / or Power plants for the use of ocean currents. Such integrative solutions offer synergy effects because existing installations of the power plant, for example, foundations, towers, Masts, generators or gears, for the storage device according to the invention can be used. Furthermore this integration offers the possibility the smoothing to carry out the electricity production at the place of production itself and thereby the power lines more evenly and thus better utilization. Offshore wind power plants are particularly suitable for this purpose. It offers the opportunity a single storage device with a power plant park Assign variety of wind power plants or several or more to give each of these wind power plants their own storage device.

Provided the power plant is designed as a wind power plant, offers the Possibility, that the drive is formed by the rotor of the wind power plant, which is mechanically connected to the buoyant body so that he over can be lowered by the rotor in rotation offset rotor. In this case, it makes sense, the generator of the wind power plant as a converter for the conversion of the kinetic energy of the buoyant body during the withdrawal of energy by using the generator mechanically with the buoyancy is connected. In this way, in the storage device according to the invention to dispense with its own drive and its own converter.

One further synergy effect leaves be achieved by the fact that the wind power plant with his mast and / or its foundation in the liquid - in offshore arrangement into the sea - dives and the buoyancy body is guided vertically movable at the dipping part of the wind power plant. This can be done on the mast of the wind power plant, or on in the Water immersed swimmers feet, though the wind power plant has a floating foundation. Unless the wind power plant In the submerged area has several columns, the buoyant body in several buoyant body subunits be split at the pillars guided are. The leadership can in any way, for example on rails or the like, respectively.

For the transmission the movement of the buoyancy body is especially suitable for a rope on which the buoyancy body is and that is connected to the drive and the converter. The flexibility allows such ropes a largely arbitrary leadership of the rope and gives considerable freedom in the formation of propulsion and converter, if that not the wind power plant itself is used, so in particular in the case of a stand-alone arrangement. For example, the rope can be guided to a station below the large fluid depth, which is provided with the drive and the converter. It exists, however also the possibility the drive and / or the converter on or on the buoyant body itself to arrange. These solutions are available in stand-alone arrangements at.

alternative For this purpose, it may be provided that the station has a deflection device has, over which has the cable connection to the drive and / or the converter. In this case, the drive and / or the converter above of the liquid level be arranged, for example in a float or when integrated with a wind or solar power plant in or on its Power plant body.

To a further feature of the invention it is provided that the buoyant body with a weight body is combined as an energy storage medium, its specific gravity is larger as that of the liquid, and that the weight body is vertical movably guided is and is connected to a drive such that the weight body through the Drive is liftable, and that the weight body with a converter such connected is that its movement when lowering into electrical Energy is converted. The weight body supports the Injection and withdrawal of energy by the buoyant body. there can buoyancy and weight body over Rope or more ropes be connected together so that they move in opposite directions - paternoster-like and over a single drive are driven and / or with a single Converters are connected.

The Arrangement of the weight body can also be above the liquid level take place, especially there the flow resistance is low. This can be combined with a wind turbine inside or on the outside happened to the mast. Especially with a stand-alone arrangement it is but for visual reasons more appropriate, the body weight below the liquid level parallel to the buoyant body to arrange so that he between a low and a high fluid depth is reciprocable while using the guide means of the buoyant body can be.

Of the body weight may for example consist of a container filled with concrete, sand or boulders. It is understood that not only a single weight body, but also several weight bodies can be provided who move in the same direction and either own drives and converters or communicate with the drive and converter with which also the buoyancy body is coupled. The combination of buoyancy and weight recommends especially if the storage device with a floating Power plant is combined. In this case, the buoyancy force the buoyancy body at least partially compensated, with a full compensation can be achieved. This will increase the stability of the floating power plant by the combination with the storage device not or only insignificantly impaired.

To the invention is further provided that the buoyancy body in several buoyant body subunits is split, which is preferably held together by a network are. Through the network, an area force can be applied become. buoyancy or on the drive body parts units can as each rigid body be formed, for example in spherical or cylindrical shape. she are then expediently hollow, but can also be filled with a closed-cell foam, so that they do not run full of leaks. Alternatively can the buoyant body or can the buoyant body parts units too from flexible containers If they have an internal support, which is a compression of the container Avoid with increasing water pressure. The inner support can for example, from a rigid foam, a liquid, the lighter than the surrounding liquid is, or consist of compressed air. However, it can also be provided a corresponding inner frame be.

The Inventive storage device is suitable also as an alternative to photovoltaic modules and accumulators for example Signal buoys or the like.

In the drawing is the invention is based on embodiments illustrated in more detail. It demonstrate:

1 a schematic representation of the principle of the storage device according to the invention in side view;

2 a first arrangement of the storage device according to the invention to a wind power plant with a firm foundation in the side view and

3 a second arrangement of the storage device according to the invention in a wind power plant with floating foundation.

In 1 is a water reservoir 1 with a water level 2 shown, wherein in the water reservoir 1 a storage device 3 is arranged. On the bottom of the water reservoir 1 is a foundation plate 4 intended. On the foundation plate 4 is a motor-generator unit 5 arranged, which can act both as an electric motor and as a generator. With the motor-generator unit 5 is a buoyant body 6 over a rope 7 connected such that upon rotation of the output shaft of the motor-generator unit 5 the rope 7 depending on the direction of rotation is rolled up or unrolled. The output shaft thus carries a winding device. Because the buoyant body 6 a lower specific gravity than the water reservoir 1 , acts on the buoyancy body 6 the symbolized by the arrow A buoyancy force with the result that the buoyant body 6 strives to move towards the water level 2 to move.

The motor-generator unit 5 has a cable, not shown in detail here connection to the electricity grid. With excess electricity and thus cheap electricity is the motor-generator unit 5 operated as Elktromotor. It drives the output shaft so that the rope 7 rolled up and accordingly the buoyancy body 6 to store energy down towards the foundation plate 4 is drawn (see arrow B). When the buoyant body 6 has reached its lowest end position, become the motor-generator unit 5 turned off and blocked the output shaft. The buoyancy body 6 then remains in this position until there is a need for energy storage due to electricity shortage. In this case, the motor-generator unit 5 operated as a generator. The blocking of the output shaft is released so that the buoyant body 6 auftrreibt, thus moving in the direction of arrow C. This generates the motor-generator unit 5 Electricity that is fed into the electricity grid and thus provides a temporary electricity subsidy. The buoyancy of the buoyant body 6 will continue as long as power shortage exists, but at most until reaching a water depth just below the water level 2 ,

In 2 is a practical application of the 1 devoted to the principle of storage. The figure shows a wind power plant 11 that a rotor mast 12 has, at the upper end, not shown, a nacelle is mounted. At the gondola is a wind rotor 13 rotatably mounted about a horizontal axis. From the wind rotor 13 Here is just the bottom of a rotor blade 14 to see. The rotor mast 12 widens conically downwards and stands in a water reservoir 15 on a foundation plate 16 lying on the bottom of the water reservoir 15 sitting. The water reservoir 15 can be a sea from a suitably deep lake or offshore. The water reservoir 15 has a water level 17 , which is 40 meters above the foundation plate 16 (see Depths on the left side of the figure).

The wind power plant 11 has in this example a maximum generator power of 5 MW. Its height is 102 m. The wind rotor 13 has a diameter of 116 m. The total weight without foundation plate 16 is 1448 t, with foundation plate 16 it is 4178 t.

On both sides of the water reservoir 15 dipping part of the rotor mast 12 is a storage device 18 intended. It has a rotationally symmetrical, the rotor mast 12 surrounding buoyant body 19 on, which consists of a plurality of stacked in three levels buoyancy sub-bodies - exemplified with 21 respectively. 22 designated - is composed. The lift part body 21 respectively. 22 the buoyancy body 19 are in a steel frame 23 fixed. The steel frame 23 is about a roller chassis 25 . 26 on rails 27 . 28 stored, which is located on the surface of the rotor mast 12 extend vertically. In this way, the buoyant body 19 vertically movable.

The lift part body 21 . 22 are designed as air-sealed, rigid container, the water pressure in the depth, up to the buoyancy body 19 is lowerable, withstand. They can be filled with closed-cell foam so that they do not fill with water in case of leaks and better withstand the water pressure. The buoyancy volume in this example is about 3100 m ³ , so that the buoyant body 19 250 kWh can afford.

The underside of the steel frame 23 is with two ropes 29 . 30 connected to the height of the foundation plate 16 via two pulleys each 31 . 32 respectively. 33 . 34 be turned upwards. The ropes 29 . 30 run along the rotor mast 12 up to the (not shown) nacelle. There is for every rope 29 . 30 a winding device is provided on which the ropes 29 . 30 can be wound up and unwound. To lower is the buoyancy body 19 via a gearbox with the wind rotor 13 and for driving also via a gearbox with the generator coupled, in the latter case, the generator of the wind rotor 13 is disconnected.

If the wind rotor 13 is driven by wind, the winders can with the wind rotor 13 be coupled via the transmission. Then the ropes 29 . 30 wound up with the result that the buoyancy body 19 from the position shown in the direction of the arrow D to the lower end of the rails 27 . 28 is lowered. In this final position they can remain indefinitely. Once the wind subsides and more electricity is needed, the generator is connected to the winders and from the wind rotor 13 uncoupled. The on drive body 19 is then driven in the direction of the arrow E, whereby in the generator electric power is generated, which can be fed into the electricity grid.

The buoyancy rate for a 5 MW generator is 0.17 m / s. The flow resistance is correspondingly low. At 30 m usable hides reaches the buoyant body 19 the upper endpoint after 182 s. If only 1 MW is generated in the generator, it will take up to the entire length of the rails 27 . 28 910 s, ie more than 15 min.

In 3 is a wind power plant 41 shown that a rotor mast 42 has, the upper portion and the seat thereon gondola are not shown. At the gondola is a wind rotor 43 rotatably mounted about a horizontal axis. From the wind rotor 43 Here is just the bottom of one rotor blade 44 to see.

The rotor mast 42 divides down in three columns 45 . 46 . 47 , which are spread apart and arranged at an angle of 120 ° to each other. The pedicels 45 . 46 47 dive into a water reservoir 48 - this may be a deep sea or a sea - one. Their ends are over ropes 49 . 50 . 51 with a swimming foundation 52 connected. Left beside the 3 a meter scale for the water depth is appropriate.

At every foot column 45 . 46 . 47 are rotationally symmetrical buoyancy bodies 53 . 54 . 55 vertically movably mounted. These are - as in the wind power plant 11 according to 2 - on the outsides of the foot columns 45 . 46 . 47 Rails provided on which drives the buoyancy bodies 53 . 54 . 55 are guided. The buoyancy bodies 53 54 . 55 can be constructed in the same way as the buoyant body 19 in the embodiment according to 2 ,

The buoyancy bodies 53 . 54 . 55 are below each with two ropes 59 . 60 respectively. 61 . 62 connected (in the buoyant body 55 at the back pillar 47 not shown), which at the lower end of the Fußsäulen 45 . 46 . 47 arranged pulleys 63 . 64 respectively. 65 . 66 to lead. In the gondola are the ropes 59 . 60 . 61 . 62 deflected by 180 ° upwards and then run on the Fußsäulen 45 . 46 . 47 and the rotor mast 42 along up to the gondola, not shown. There is for every rope 59 . 60 . 61 . 62 a winding device is provided on which the ropes 59 . 60 . 61 . 62 can be wound up and unwound. To lower the buoyancy bodies 53 . 54 . 55 via a gearbox with the wind rotor 43 and for driving also via a gearbox with the generator detachable, in the latter case, the generator of the wind rotor 43 is disconnected.

If the wind rotor 43 is driven by wind, the winders can with the wind rotor 43 be coupled via the gearbox. Then the ropes 59 . 60 . 61 . 62 wound up with the result that the buoyancy bodies 53 . 54 . 55 from the position shown in the direction of the arrow F to the lower end of the Fußsäulen 45 . 46 . 47 be lowered. In this end position they can remain indefinitely. Once the wind subsides and more electricity is needed, the generator is connected to the winders and, if necessary, from the wind rotor 43 uncoupled. The buoyancy bodies 53 . 54 . 55 are then driven in the direction of arrow G, thereby generating in the generator electrical power which can be fed into the electricity grid.

Claims (43)

Method for the alternate storage and withdrawal of energy for the purpose of temporary generation of electrical energy, in which an energy storage medium ( 6 ; 19 ; 53 . 54 . 55 ) for storage by means of a drive ( 5 . 13 . 43 ) is transported from a low energy potential by overcoming a height difference to a high energy potential and can be kept there ready for retrieval and in which the energy storage medium for the withdrawal moves in the reverse direction and the energy released by a converter ( 5 ) is converted into electrical energy, characterized in that as an energy storage medium into a liquid ( 1 . 15 . 48 ) immersed buoyancy body ( 6 ; 19 ; 53 . 54 . 55 ) whose specific gravity is lower than that of the liquid ( 1 . 15 . 48 ), and that the buoyancy body ( 6 ; 19 ; 53 . 54 . 55 ) is lowered for storage in a large liquid depth in order to achieve a high energy potential and is there on call durable and that the buoyancy body ( 6 ; 19 ; 53 . 54 . 55 ) is driven to the storage in the direction of the low fluid depth and thereby via the converter ( 5 ) generates electrical energy. Process according to claim 1, characterized in that as liquid ( 1 . 15 . 48 ) Water is used. Method according to claim 2, characterized in that that the procedure is applied in the sea or in a lake. Method according to one of claims 1 to 3, characterized in that that of the converter ( 5 ) generated electrical energy is fed into an electricity grid. Method according to claim 4, characterized in that that the electrical energy is only fed into the electricity grid will if needed for electric current exists. Method according to one of claims 1 to 5, characterized in that the buoyant body ( 6 ) for the storage of energy by means of an electric drive ( 5 ) is lowered. A method according to claim 6, characterized in that the electrical energy for the drive ( 5 ) is obtained from the electricity grid. Method according to claim 7, characterized in that that the electrical energy from the electricity grid is only recovered if a surplus consists of electricity. Method according to one of claims 6 to 8, characterized in that the electrical energy is obtained by means of a power plant, the Electricity generated from renewable energy, which is fluctuating, and that electrical energy is supplied to the drive only when the energy production exceeds a certain value. Method according to one of claims 1 to 9, characterized in that the buoyancy body ( 19 ; 53 . 54 . 55 ) is lowered for the storage of energy by means of a mechanical drive, as a wind power plant ( 11 . 41 ) with a rotor ( 13 . 43 ) or is designed as a marine power plant with a rotor which forms the mechanical drive. Method according to one of claims 1 to 10, characterized that additionally uses a weight body as the energy storage medium whose specific gravity is greater than that of the liquid, and that the weight body is raised for storage by means of a drive and there is stable and ready to be stored and that the weight body lower for withdrawal is left, wherein the weight body via a converter electrical Energy generated. Storage device for the alternate storage and withdrawal of energy for the temporary generation of electrical energy, with an energy storage medium ( 6 ; 19 ; 53 . 54 . 55 ), which by means of a drive ( 5 . 13 . 43 ) is transportable from a position of low energy potential by overcoming a height difference in a position of high energy potential and is there on call durable and which is movable to the withdrawal in the reverse direction and thereby to a converter ( 5 ) acts to convert the released energy into electrical energy, characterized in that the energy storage medium as a liquid in ( 1 . 15 . 48 ) immersed buoyancy body ( 6 ; 19 ; 53 . 54 . 55 ) is formed whose specific gravity is lower than that of the liquid ( 1 . 15 . 48 ), and that the buoyancy body ( 6 ; 19 ; 53 . 54 . 55 ) is movably guided between a large and a low liquid depth and with the drive ( 5 . 13 . 43 ) is connected such that the buoyancy body ( 6 ; 19 ; 53 . 54 . 55 ) by the drive ( 5 . 13 . 43 ) is lowered from the low liquid depth into the large liquid depth, and that the buoyancy body ( 6 ; 19 ; 53 . 54 . 55 ) with the converter ( 5 ) is connected in such a way that its movement in the direction of the low water depth is converted into electrical energy. Storage device according to claim 12, characterized in that the liquid ( 1 . 15 . 48 ) Water is. Storage device according to claim 13, characterized in that that the storage device on or in a sea or on or is arranged in a lake. Storage device according to one of claims 12 to 14, characterized in that the drive ( 5 ) is an electric motor. Memory device according to one of Claims 12 to 15, characterized in that the converter ( 5 ) is a generator. Storage device according to claim 15 and 16, characterized in that the electric motor and generator are a unit ( 5 ) form. Storage device according to one of claims 15 to 17, characterized in that the drive ( 5 ) is connected to an electricity grid. Storage device according to one of the claims 12 to 18 , characterized in that the converter ( 5 ) is connected to an electricity grid. Storage device according to one of claims 12 to 19, characterized in that a power plant ( 11 . 41 ), which generates electricity from fluctuating, renewable energies. Storage device according to claim 20, characterized in that the power plant is a wind power plant ( 11 . 41 ) with a rotor ( 13 . 43 ) and a generator and / or a solar power plant and / or a marine power plant. Storage device according to claim 21, characterized in that the drive from the rotor ( 13 . 43 ) of the wind power plant ( 11 . 41 ) or of the marine power plant, which is mechanically connected to the buoyant body ( 19 ; 53 . 54 . 55 ) is connectable. Storage device according to claim 21 and 22, characterized in that the converter is the generator of the wind power plant ( 11 . 41 ) which is mechanically connected to the buoyant body ( 19 ; 53 . 54 . 55 ) connected is. Storage device according to one of claims 21 to 23, characterized in that the wind power plant ( 11 . 41 ) partially into the liquid ( 15 . 48 ) and the buoyancy body ( 19 ; 53 . 54 . 55 ) at the immersed part of the wind power plant ( 11 . 41 ) is guided vertically movable. Storage device according to claim 24, characterized in that the wind power plant ( 41 ) in the submerged area several columns ( 45 . 46 . 47 ) and the buoyancy body ( 53 . 54 . 55 ) is divided into a plurality of buoyant body subunits which are attached to the columns ( 45 . 46 . 47 ) are guided. Storage device according to one of the claims che 12 to 25, characterized in that the buoyancy body ( 6 ; 19 ; 53 . 54 . 55 ) on a rope ( 7 ; 29 . 30 ; 59 to 62 ), which is connected to the drive ( 5 . 13 . 43 ) and the converter ( 5 ) connected is. Storage device according to claim 26, characterized in that the rope ( 7 ) is guided to a station below the large liquid depth, with the drive ( 5 ) and the converter ( 5 ) is provided. Storage device according to claim 26, characterized that the drive and / or converter is arranged on or on the buoyant body is or are. Storage device according to claim 26, characterized in that the rope ( 29 . 30 ; 59 to 62 ) is guided to a station below the large liquid depth, wherein the station is a deflection ( 31 to 34 ; 63 to 66 ), over which the rope ( 29 . 30 ; 59 to 62 ) Connection to the drive ( 13 . 43 ) and / or the converter. Storage device according to claim 29, characterized in that drive ( 13 . 43 ) and / or transducers are arranged above the liquid level. Storage device according to claim 30, characterized in that a wind power plant ( 11 . 41 ) with a rotor ( 13 . 43 ) and a generator and that the converter is the generator of the wind power plant ( 11 . 41 ). Storage device according to one of claims 12 to 31, characterized in that the buoyant body with a weight body as Energy storage medium is combined, its specific gravity is larger as that of the liquid, and that the weight body is guided vertically movable and connected to a drive such that the weight body through the drive is liftable, and that the weight body with a converter such connected is that its movement when lowering into electrical Energy is converted. Storage device according to claim 32, characterized that buoyant body and weight body over or more ropes are connected together so that they themselves move in opposite directions and over a single drive are driven. Storage device according to claim 32 or 33, characterized characterized in that the weight body above the liquid reservoir movably guided is. Storage device according to claim 32 or 33, characterized characterized in that the weight body is movably guided in the liquid reservoir. Storage device according to one of claims 12 to 33, characterized in that the buoyancy body ( 19 ) into a plurality of buoyant body subunits ( 21 . 22 ) is divided. Storage device according to claim 36, characterized in that the buoyant body subunits ( 21 . 22 ) by a frame ( 23 . 24 ) or a network are held together. Storage device according to one of claims 12 to 37, characterized in that the buoyancy body ( 6 ; 19 ; 53 . 54 . 55 ) or the buoyant body subunits ( 21 . 22 ) is formed as a respective rigid body. Storage device according to one of claims 12 to 38, characterized in that the buoyancy body ( 6 ; 19 ; 53 . 54 . 55 ) or the buoyant body subunits ( 21 . 22 ) consist of one or more flexible containers having an inner support. Storage device according to claim 39, characterized that the inner support off consists of a rigid foam. Storage device according to claim 39, characterized that the inner support off Compressed air exists. Storage device according to claim 39, characterized that the inner support a liquid which is lighter than that of the liquid reservoir. Storage device according to claim 39, characterized that the inner support off a scaffold exists.